A valve of the type mentioned at the outset is known, for example from U.S. Pat. No. 5,791,557, wherein a bypass conduit is provided which keeps the inlet for oil coming from the transmission connected with the outlet to the transmission as long as the thermostatic actuating element has not yet reacted. When the thermostatic actuating element reacts because of a temperature increase in the oil, the bypass is closed. In extreme weather conditions, it is possible that this thermostatic valve does not supply sufficient oil to the automatic transmission and is therefore damaged. If there are very cold outside air temperatures, it can happen that the oil leaving the transmission and flowing in the bypass is heated to such a degree that the thermostatic actuating element reacts and opens the connection between the inlet conduit for the oil coming from the transmission and the outlet conduit to the oil cooler and blocks the bypass. However, the very cold outside temperatures can lead to the oil in the oil cooler being cooled to such a degree that the flow resistance in the oil cooler becomes so great that insufficient oil flows back to the automatic transmission.